A 16-year-old boy has been arrested in Britain on suspicion of cybercrime.
The teenager was arrested at a south London address on Tuesday and taken to a central London police station, where he remains in custody, police said.
He was held on suspicion of breaching the Computer Misuse Act 1990.
The Metropolitan Police is liaising with the FBI and authorities in the Netherlands, a police spokesman added. It is understood that he is suspected of being connected with hacking group Anonymous.
It came as 14 people were arrested in the United States for allegedly mounting a cyberattack on PayPal's website in retaliation for suspending the accounts of WikiLeaks.
The attacks on the online payment specialist by the group Anonymous followed the release by whistleblowing website WikiLeaks in November of thousands of classified US State Department cables.
Anonymous, a loosely-organised group of hackers sympathetic to WikiLeaks, has claimed responsibility for attacks against corporate and government websites all over the world. The group also claims to have disrupted the websites of Visa and MasterCard in December when the credit card companies stopped processing donations to WikiLeaks and its founder Julian Assange.
The 14 allegedly involved in the PayPal attack were charged in US District Court in San Jose, California, and were arrested in Alabama, Arizona, California, Colorado, the District of Columbia, Florida, Massachusetts, Nevada, New Mexico and Ohio.
Meanwhile, FBI agents executed more than 35 search warrants around the country in an continuing investigation into coordinated cyber attacks against major companies and organisations.
There were two arrests in the United States unrelated to the PayPal attack and four arrests by the Dutch National Police Agency.